The present invention relates to a method and apparatus for pulling crown plugs from deep sea horizontal christmas trees using a jacking apparatus, jacking string located subsea during the pull, and control panel which is located at the surface of the water.
Subsea oil and gas production wells can be sealed off from the sea using production christmas trees. Two types of trees are commonly used: (1) vertical trees and (2) horizontal trees. Vertical trees include gate valves in the production bore which can isolate the well bore. Horizontal trees include crown plugs for sealing their production bores which plugs are run into tubing hangers and installed inside the tree.
Horizontal christmas trees are increasingly being used because of their lower costs and increased functionality compared to vertical trees. For example, horizontal trees typically bring wells into production in shorter periods of time compared to vertical trees. Furthermore, horizontal trees provide the flexibility of using larger bore completion systems.
Notwithstanding their benefits compared to vertical trees, horizontal christmas trees encounter problems with removing stuck crown plugs. Stuck crown plugs can require excessively large pulling forces to unstick and retrieve the plugs from the tree. It is important that the crown plugs, even when stuck, be removed so that downhole operations can be performed in the well when desired.
There is a need for providing a method and apparatus for removing stuck crown plugs using a wireline or slickline retrieval system.
While certain novel features of this invention shown and described below are pointed out in the annexed claims, the invention is not intended to be limited to the details specified, since a person of ordinary skill in the relevant art will understand that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation may be made without departing in any way from the spirit of the present invention. No feature of the invention is critical or essential unless it is expressly stated as being “critical” or “essential”